This invention relates to a substrate carrier for a vacuum coating apparatus for the vacuum evaporation and deposition of antireflection coatings onto optical substrate surfaces, such as plastic spectacle lenses. The substrates can be clamped to a plurality of carriers located above replaceable evaporation sources in a vacuum container.
In known apparatus of the above type designed for the evaporation and deposition of at least one layer onto optical substrates in a vacuum, a predetermined number of such substrates are removed from the plane in which vapor deposition of one or more layers was carried out, and an equal number of substrate surfaces are moved into such plane so that these can subsequently also be coated once or several times.
For this purpose a turntable which can be placed under vacuum may be used. Such a table may be provided with a plurality of stations arranged around its circumference for the releasable fastening or subs-rates. This apparatus further comprises at least one evaporation source serving the facing substrate surfaces. Each station is provided with a substrate carrier provided with holding means for releasably fastening the respective substrates. If the individual antireflection coatings have been deposited successfully on one side of the substrate surfaces, the substrate carriers are reversed by rotating the turntable, whereupon the other substrate surfaces are coated.
Furthermore, it is known to design substrate carriers as so-called calottes for positioning a plurality of substrates on the planar, circular-segment shaped carriers. A plurality of such calottes extend dome-shaped and rotatably in the upper portion of the container, and with each calotte a plurality of substrates may be rotated simultaneously.
It is a difficulty with such arrangements that the coating stream that rises conically in the center of the container requires an exact angular position of the substrate surfaces to the conical stream in order to achieve an optimum precipitation coating, on each surface.
If the substrate carriers with one substrate each, are arranged such that they radially project from a turntable and can be rotated by 180.degree. by a shaft, a uniform precipitation can be achieved easily by an oblique orientation of the shafts. Such a solution, however, may not be sufficient for the calotte-shaped substrate carriers where a plurality of substrates are to be mounted on the planar, circular-segment shaped carriers.
Therefore, calotte-shaped substrate carriers of the above type have been provided with substrate holders which, together with the substrate, can be freely tilted from the plane of the carrier plate to either side up to a predetermined angle. Such substrate holders, however, are. very complicated and prone to failures.